Remote control system



Dec. 27, 1949 P. K. EcKHARDT REMOTE CONTROL SYSTEM Filed Feb. 17, 1949EN- n INLEVTOR Paal K. Eckhardt 0. Z. M H15 ATTORNEY Patented Dec. 27,1949 ED :2,492,399 Y Y I l .nEMoLrE .ooN'raoLsXs'rEn/i paul K. Eckhardt,einem \frnwns'h^ip, anegheny Signal Humana, .Swissvala JBa.,:. a,:corporation of Pennsylvania 21 IMy 'invention relates Ltoremote-control systems and more partieii-larly to 'centralized traicoontrolrsystemsi-forrailroads; inwliicntrafc gever-n ing devices`-loc-ated along L'a ftraclevvayV aref-governed ff-isoma controlcnice-andthe'conditionsof the udc-:vices and associated A-fappaiatasiare "indicaltedatisucheice.

"llnfsystems of vtlieftype described, vith-e ioice is linked 'witnthetrallic fgoverning devices iaklong the -ltrackway 'fby ymeans 'of .1acommunicatiotnssystem winch may be-lof any'suitabletypaesuch lforf.example, .thefditect -wire, `carrier:selectableor codeiltype,onefexample -of the -latter being-sham Letters Patent .of ftheU-nitediStatesNo.; 2,.fii1i1y- 3'25, granted November x19, .L1-946,onranapplnationiled Joy Arthur1P.alackel, .foriRemote controlfrsystems.

f y,In a node system of the :type mentioned, steps in tlielindicati'on.'codefare iu'sedfas achannels vice. .':Eor examplefza tnack'switchiszaethree-ipsition devicethavrrg:amomnal,iazreverseaandvansinetermediate position and is indicated over itwo ,channels .arranged :insuch lmanner that one channel indicates Whether or not the switch lockedin its normal position, tandritheiotherfcnannel indicates whether @ornot :the-switch locked in its teverse position. Thus whenfthefswitch @islooked in either its normalorits reverse gnsition itpnovides oneyenana-eter for thecoderstep which indicates thatfthe switch is lockedl.in;the-.l, r1'.e spondingjposition, .and provides a :different cha-r-`yactor for the other code step. When'tl-ie switch is unlocked .by theswitch fmachinaiasiwhenrthe switch pointsiare in transit.betweenextnemepositions7 the code intervals of the twoswitcn indicationsteps both have the -diierent character mentioned, to indicatethetransitvcondition. 'Ihe two steps are capable -of indicating aiourthcondition if both have the one character referred Pto, but -the switchvobviouslyis not adapted toaford a control which establishesjtliischaracter v`for .both steps, and the full capacity of tliefcodefor.- fdinarily is .not utilized.

It ,has been proposed heretofore to makeusetof this fourth codecondition (in which bothsteps havethe one code character) -to indicate a`two- .position device, for example, asshown in theseending applicationfor Letters Patent of 'the United States, Serial No. 665,018, led vA1.'1-i1.26 v1946, byJoseph A. Quinlan; .zin iI etters'lPatent of .theUnited States No. 2,460,336, granted :February l, v1949, to Ira F.Cadrnan; and :in :Letters IPatentxof the .United States No.2,46Qi33i7gifanted Februaryl, .1949, toHenrwES. Young; all of havebeenassignedtothe assignee -of the present lis;

application,

@ne -obj'e'c-t--of'my Einvention'is to provide `novel and impiovednneansin IWl'xiclr-the two indication channels "of' a "centralized trafficcontrol gsystem required-@to A:indicate atlrreeposition-device alfastation, are employed Vrto indicate Lalso 'a two-fpositiondevieelat thatstation.

Anotnerfobjectof myinvention istwprovide'an improved systempi'the typeshownlin the-aforementioned Qn'irilan application viSerial No. 665;- lS,in wnienthere =`-is obtained an 'additional fin dieet-ien f relatingto-a *twodposition device ontw@ indication steps :fo'La eotle Iwhich "arenorm-ally arrangedto tprov-ide three indications one vfor eachpositioneo'f a -ftnree-*position Idevice, LWlfiiclfiadditionalindication#isipifovided'by means which function to indicatev1' changes imposition o`fbotl1 of the devicesfon oteither-oi-themWithout-affect- Ling-'tideindicationfof-the other.

A sspecilcfobject oflrnyinventi'on is to simplify and 41iii-riprovofthenpparatus shownfin Athe-I'Qu'inlan application, Serial `fNo.v665,1018, for 4.utilizing the indicationsteps which indicate theAposition df la 'iremotely :controlled Apowersepeifated track switch iteindicate .also #a jtwo-position :device at the locationpf such trackiswiitdh. @ther 'deatmres of my iinilenti'on willibe ipointedientindietal-infith'e iaceompanying. specification.

I sh-all fdes'cnibe 'itwo forms fof .apparatus 1embodningnmyziinventicn,and -sh-al1 thenpoint out the mvel'leamnres .thereof {infcl-aims.

.':In'iiihe accompanying idaawingsraljlig. 1 aisfa d1'- agizamnraticvewillustrating .fone ifonm of appa.- natus 'nrbodyingemyfinvention. Fig.12a :is Aa .view slriowinga'imo'died iiorm dfzthesappazr'atus kshown inE'igAl. JIniEig. Y ita, [each :of the circuitselements is identified-byreference -:characters :corresponding :ato :these fused iin lii'g. l1and it 'Will-ipe :understood that the designation :di a relay .lof-iEig.2l placed alo-ove af-i=elayfconltact oflilig. v:lotindicates tliatfsnchanentactfis-operated by the :velay thus identified',v as forL example,Eltlfie--designation lNVS/P placeda'bove fconltact 53 of ilu flindicatesthat contact is operated fby itelay-:NWP lllus'trated lin Figfl i f.Reieifiling v1tothe'difavvfing,a centralized traffic control system isrepresented jas coin-piising apparatus .at f an iof'ce :andvatyiastation, fand "al-commuri-ication: systein linking itl-1e fol'ce withfinestration.

' The fcommunicationsys'tem, `vvhichfas previously imentione'd -may AdoeJ'of -any' suitable f type, is conven'tionalle7 "represented in"tlrefldrawing as beingia code system fof theitype 'illustrated-iin ithepreviously mentioned Jackel patent. For the purposes of explaining thepresent invention it is sufcient to state that the communication systemprovides a number of control channels (not represented in the drawing),and a number of indication channels some of which are represented in thedrawing by dash lines, with the wires of each channel designated byreference characters which are the same as those used to designatecorresponding wires in the Jackel patent. For example, the indicationchannels 49--l39 and l-l4l represent individual code steps of anindication code, and the system functions in the manner explained in theJackel patent so that if one terminal B of a suitable local source ofcurrent at the station is connected to wire l39 when an indication codeis transmitted, the code will include a step of a particular charactercorresponding to the energization of channel 14S-|39, to cause terminalB of y a source at the olice to be applied to terminal 49. If terminal Bis not connected to wire |39 when an indication code is transmitted, thecode will include a step of a different character corresponding to thedeenergization of channel 1S-|39, and in such case terminal B at theoice is not applied to wire 49. Similarly, if terminal B at the stationis connected to wire |4I when an indication code is transmitted, thecode will include a step of a particular character corresponding to theenergization of channel 5l-I4l to apply terminal B at the oice to wire5l, but if terminal B at the station is disconnected from wire IM whenan indication code is transmitted, the code then includes a step of adiierent character corresponding to deenergization of channel 5I-I4l.

The apparatus at the oice, as indicated in the drawing, includes an omcedelivery relay D which corresponds to the oloe delivery relay D of the Jackel patent and which is picked up at the oflce at the end of acomplete indication code received from the station, as is explained indetail in the Jackel patent, and a normal indication relay NWK and areverse indication relay RWK selectively picked up according as energyis applied to terminal 49 or 5l at the oiiice when the oce deliveryrelay D is picked up. The pickup circuit of each indication relayincludes a back contact of the other indication relay so that each relayNWK or RWK when picked up opens the pickup circuit of the other relay toinsure that only one of the two indication relays can be picked up atany time. Each relay NWK or RWK when picked up is held energized over astick circuit including its own front contact and a back contact ofrelay D, when the latter relay releases at the end of an indicationcode. Indioation lights NWE and RWE are controlled respectively byrelays NWK and RWK so as to be illuminated or dark according as theassociated relay is picked up or released.

In addition to the apparatus above described, I provide in accordancewith my invention an omce intermediate relay OIR, another indicationrelay CHK, and two other indication lamps ICCK and ZCCK. Theintermediate relay OIR is arranged as will be explained in detailhereinafter to pick up whenever` both indication relays NWK and RWK arereleased, or whenever with either of those two indication relays pickedup, an indication code is received which includes a step of thecharacter corresponding to the energization of the channel of the otherindication relay. Relay OIR has a stick circuit which includes its ownfront contact and a front contact of the delivery relay D. Relay CHK isarranged to pick up if with either of the two indication relays NWK orRWK picked up, an indication code is received which places energy onboth indication channels so that the picked up indication relay is heldup, the intermediate relay OIR becomes picked up, and when relay D picksup relay CHK is energized and picks up. Relay CHK when picked up attimes is provided with a stick circuit which of course includes a frontcontact of the relay, and has a number of branches, one completed whenrelay D is released, and others completed with relay D picked up, aswill be explained in detail hereinafter. Relay CHK controls indicationlamps l CCK and 2CCK so as to energize one or the other of such lampsaccording as the relay is released or picked up, respectively.

The apparatus at the station includes a plurality of elements, such as asignal (not shown) a, three-position device, such as a track switch Wprovided for a stretch of track and having a normal, a reverse, and anintermediate position, a power switch operating mechanism SM operativelyconnected with the switch for operating it between its two eXtreme(normal and reverse) positions and controlling a contact l according tothe position of the switch, switch repeating relays NWP and RWPselectively energized over contact I according as switch W is locked inits normal or reverse extreme position, a track relay TR connected in atrack circuit including a track battery TB, provided for the tracksection T which includes the point of switch W, a starting relay ST anda neld station disconnect relay RPP corresponding respectively to thesimilarly designated relays shown in the Jackel patent, a eldintermediate relay FIR hereinafter referred to, and a two-positiondevice (such as a relay CH) which is to be indicated at the omce on theswitch indication steps by use of my novel and improved arrangement ofapparatus.

The switch operating mechanism SM is controlled by means of apparatusand equipment not illustrated in the attached drawing for the sake ofsimplicity but which may take the form shown and described forcontrolling the switch IW of the Jackel patent. For the purposes of thepresent description it is sufficient to state that the systemorganization is such that the operator at the ofce is enabled to controlthe switch mechanism SM to cause it to operate the switch W to and lockit in its normal or reverse position, it being understood of course thatthe switch can be unlocked by the switch mechanism for movement onlywhen traic 4conditions on the stretch are favorable for such operation.

The starting relay ST is controlled in the manner explained in detail inthe J ackel patent, and is normally energized over a stick circuit whichincludes contact 2 of relay ST (closed in the energized position of therelay in which contact 2 operates to its left-hand position as viewed inthe drawing) the winding of relay ST and contacts of each of the relaysNWP, RW?, TR, FIR, and CH. Alternatively, as indicated in Fig. la, thestick circuit of relay ST may be arranged to include a contact of relayFIR only when relay CH is in its operated or right-hand position, aswill be made clear presently. In either case the stick circuit of relayST may also include contacts of other relays such as shown in the Jackel patent, and the arrangement is such that upon change in positionof any of the relays having a contact in the stick circuit of relay ST,the stick circuit is opened and relay "ST operates its -contacts totheir righthand positionV in which contact I4 closes to initiate thetransmission of an indication code to the oflice in the manner explainedin the Jackel patent. After the transmission of a portion (the stationregistering part) of that code has been completed, the station apparatusis arranged to pick up relay ST over a circuit in which terminal B isapplied to wire I I4 in the manner pointed out in the J ackel patent,whereupon relay ST operates its contact 2 to its normal or left-handposition to re-establish its stick circuit. I

The eld station disconnect relay RPP is controlled in a manner (notshown in the drawing to lavoid unduly complicating it) corresponding tothat illustrated and described for the correspondingly designated relayof the Jackel patent, and for lthe purposes of the present applicationit is deemed suicient to state that relay RPP remains energized in thenormal operation of the system, but can be deenergized at the will ofthe operator in the oice through the medium of the communication system.Relay RPP when released renders the `associated station equipmentinactive so that indication codes cannot be transmitted.

The field .intermediate relay FIR is picked up whenever relay RPP isreleased to close its back contact I5 to complete an obvious circuit for.relay FIR, -orwhenever both relays NWP and .RWP are .released withrelay RPP picked up, in which eventrelay FIR is energized over a circuitwhich may be traced from terminal B through back contact I6 Ioi' relayNWP, back contact IFI of rel-ay RWP,.front contact I5 of relay RPP an-dthe winding of relay FIR to terminal C. Relay FIR is provided with astick circuit completed when contact I4 of relay ST is closed in itsoperated or right-hand position (in which the transmission of anindication code is initiated) provided that relay ARPP and either one orboth of the switch repeating relays ,are picked up. The stick circuit.may be traced from terminal B through contact I4 of relay ST in itsright-hand position, front contact .I8 of relay FIR, .and either frontcontact Il of relay RWP, or front contact I6 .of relay NWP and backcontact I1 of relay BWP., and then through front contact I5 of .relay.RPP and the winding of relay FIR to terminal C.

The two position device which is to be indicated at the cnice throughthe medium of my novel and improved arrangement utilizing the two codesteps which indicate the three-position track Switch, may Yas shown be atwo-position relay CH corresponding to relay ZCH illustrated anddescribed in Letters Patent of the United l.States No. 2,350,668, issuedJune 6, .1944, on an application led by George W. Baughman and Norman F.Agnew. As Vexplained in the Baughman et al. patent, the relay CH mayfunction asa carrier change over relay controlled from the oflice forselecting one or the other of two .carrier current unitslCCU and 2CCUconventionally represented -atthe station. It should be understood,however, that the same principle may be applied to indicate anytwo-position device, such as the grpower-oil .relay POR shown in theQuinlan application Serial No. 665,018, and is applicable whetherpolarized or neutral two-position relays are employed.

The previously mentioned switch indication relays 'NWP and RWP governthe transmission -of switch indications from the station in the usualmanner. That :is to say, it is obvious from an inspection oi the drawingthat if an indication code is transmitted from the station when relayNWP is picked up, wire |39 will be connected to terminal B at frontcontact 8 `of relay NWP, and that when a code is transmitted with relayRWP picked up, wire I4I will be connected to terminal B at front contact9 of relay R- In addition, the relays NWP and RWP cooperate with relaysCH and FIR to connect terminal B to both wires |39 and I4I if anindication code .is transmitted when relay CH is in its operated (orrighthand) position, relay FIR is released, and either relay NWP or RWPis picked up. If, for example, under the conditions assumed relay RWP ispicked up toconnect terminal B at its front ccntact 9 to wire I4I, thenterminal B at contact I of relay CH is connected to wire 13% over acircuit including contact I0 of relay CH in its righthand position, backcontact II of relay FIR, iront contact I3 of relay RWP and back contact8 of relay NWP. lThe relays CH and FIR therefore function under certainconditions to control the transmission of the fourth condition of theswitch indication code, i. e, both steps having the one code character,which is utilized in a manner hereinafter pointed out to control at thecnice the indicating lamps ICCK and ,2CCK. The provision of thisindication is of particular advantage in connection with remote controlsystem-s, since it may be utilized to convey information relative to theposition of a carrier changeover relay in systems using duplicatecarrier current units', or the position of a power-olf relay, .or :othertypes of equipment employed in remote control .systems and having twopositions such as a normal position and an operated position. Thus inthe case of the carrier changeover relay it enables the operator `tohave information provided ,as to which of the two duplicate sets ofcarrier equip-- ment is in service, while in the case of the poweroffrelay information is furnished as to whether the equipment at .the iieldstation is operating from the normal source or being energized from thestandby power source.

The condition of the apparatus shown inthe drawing is that obtainingwhen switch W is locked in its normal position `and relay CH is in yitsnormal, or left-hand position as viewed in the drawing in which contactI 9 of .relay CH selects carrier unit ICCU. In this condition of theapparatus relay NWP is picked up over contact I of switch mechanism SMand the relay holds its front ,contact 8 closed to prepare the circuitfor connecting terminal B at the station to terminal l|39 'of one of theswitch communication channels of the code. Relay ST also is energized inits stick circuit including its contact 2 closed in its energized, orleft-hand position as shown ,in the drawing, the winding of relay ST,front contact 3 of relay NWP, back :contact 4 of relay RWP, frontcontact 5 of Vrelay FIR, front contact S of relay TR, contact 1 of relayCH in its normal or lefthand position, and the other terminal :C of theenergizing source oi current. At the office, relay NWK is held energizedover its stick circuit including front' contact 2I of relay NWK andhackcontact 22 -of relay D; and front contact 2.3 of relay NWK is heldclosed to complete an obvious energizing circuit for indication lamp NWEwhich reflects at the -oflice the locked normal condition occupied bythe track switch at the station. In addition, indication lamp 1I CCK 'isenergized :over back contact 24 of relay CHK to indicate at the office.that vcarrier unit ICCU at vthe station is vselected for operation. v

With relay VCI-I in its normal or left-hand position as illustrated inthe drawing, the apparatus embodying my invention operates tocontrol theindication lamps at the oilice, and particularly the switch indicationlamps NWE and RWE, in accordance with indication codes transmitted fromthe station following a change in condition of the apparatus at thestation, While maintaining the indication at the oce reflecting theposition oi the carrier change-over relay CH at the station. Forexample, if a change occurs in the occupancy of track section T so thatrelay TR releases to reilect the presence of a train (or if relay TRsubsequently picks up to indicate the train vacating the section), theshift in position of contact 6 of relay TR will momentarily open at thatpoint the stick circuit of relay ST, and that relay will operate itscontact I4 to its right-hand position to initiate an indication code. Inthis code terminal B at contact 8 of relay NWP is connected to terminalI 39 so that terminal B at the oilice will be connected to terminal 49.When relay D at the oce picks up to open its back contact 22 in thestick circuit of relay NWK, and contact 22 of relay D in its frontposition thereupon ycompletes the pickup circuit for relay NWK extendingfrom terminal 49 through back contact 25 of relay RWK, front contact 22of relay D and the winding of relay NWK to terminal C. Relay NWK willtherefore be held energized as long as relay D is held up, and whenrelay D releases its back contact 22 closes to re-establish the stickcircuit of relay NWK so that the display of the switch indication lampNWE is maintained. The starting relay ST will have been restored to itsnormally energized condition in the manner explained in the Jackelpatent, after transmission of the station selecting portion of theindication code.

If, under the conditions assumed, the operator controls the switchmechanism SM to operate switch W to its reverse position, relay N`WPwill become deenergized as soon as mechanism SM unlocks the switchpreparatory to operating it to the reverse position, and relay FIR willpick up over its circuit including back contacts I 6 and I'I of relaysNVVP and RWP, respectively, so that relay FIR closes it front Contact I8to prepare its previously traced stick circuit.V In addition; thestarting relay ST will operate to its righthand position to initiate anindication code in which .both terminals I39 and I4I at the station willbe deenergized due to the fact that both relays NWP and RWP arereleased. Under these conditions both terminals 49 and 5I atA the oicewill be deenergized when relay D picks up, so that when back contact 22of relay D opens, relay NWK becomes deenergzed and releases to open itsfront contact 23 and deenergize lamp NWE, thereby to indicate thatswitch W at the station is in transit between its two extreme positions.Relay OIR at this time picks up over an obvious circuit including backcontacts 2E and 2'I of relays NWK and RWK and winding 28 of relay OIR;and relay OIR establishes a stick circuit including front contact 29 ofrelay D, front contact 30 of relay OIR and winding 28 of that relay.This stick circuit opens as soon as relay D releases, but relay OIR isheld energized over its pickup circuit as long as both relays NWK andRWK remain released.

At the station, relay RWP picks up as soon as contact I is operated toits reverse position to indicate that switch W is operated to and lockedin its reverse position, and back contact 4 of relay RWP opens todeenergize relay ST so that its contact I4 operates to its right-handposition to complete the stick circuit of relay FIR through contact I4of relay ST, front contact I 8 of relay FIR, front contact I'I of relayRW'P and front contact I5 of relay RPP. Contact I4 of relay ST alsostarts transmission of another indication code in which terminal B atcontact 9 of relay RWP is connected to terminal I4I so that terminal Bat the oiice is connected to terminal 5I when relay D picks up, and as aresult relay RWK at the oiiice picks up over a circuit which passes fromterminal 5I through back contact 3| of relay NWK, front contact 32 ofrelay D and the winding of relay RWK. Relay RWK thereupon opens its4back contact 2'I in the circuit of winding 28 of relay OIR, but thatrelay remains energized over its stick circuit including its own frontcontact 30 and front contact 29 of relay D. Front contact 33 of relayRWK closes to energize lamp RWE to indicate that switch W at the stationis locked in its reverse position, while front contact 34 of relay RWKalso closes to prepare its stick circuit which is completed and holdsrelay RWK energized when relay D releases to close its back contact 32.

Relay FIR at the station became deenergized during the transmission ofthe indication code just described, when relay ST restored to normal tooperate its contact I4 to its left-hand position at the end of thestation selection portion of the indication code, but due to the slowreleasing characteristics of relay FIR its armature was retained in itspicked up position during the transmission of the remainder of the code.It should be noted that during this period back contact II of relay FIRwill be held open, and that after the full indication code has beentransmitted from the station and registered at the oce, relay FIR willrelease at the end of its slow release interval to close its backcontact II, and to shift the position of its contact 5 in the circuit ofrelay ST, whereupon relay ST operates to initiate another indicationcode. In this code terminal B at the front contact of one of the switchindication relays (RWP) is connected to one of the wires I4I, while withback contact II of relay FIR closed, and one switch indication relay(RVVP) picked up and the other relay (NWP) released, a circuit isprepared for connecting terminal B at contact IIl of relay CH to theother wire I39. Under the conditions assumed, however, that is, withrelay CH in its normal or lefthand position, terminal B is not connectedto wire I39 during this code and as a result terminal B at the officewill be connected only to wire 5I, to hold up relay RWK when relay Dpicks up, and when relay D releases relay RWK remains held up over itsstick circuit.

It is believed that the operation of the apparatus in response to theswitch W being restored to its normal position with relay CH also in itsnormal position, will be readily apparent from the foregoing descriptiontaken in connection with an inspection of the drawing, it beingunderstood of course that the apparatus will first function to transmitan in-transit indication during which relay FIR at the station is heldenergized and the two wires I39 and I4I at the station are bothdeenergized; that following the switch becoming locked in its normalposition a normal-position code will be transmitted during which relayFIR is held up and wire I39 at the station is energized; and that afterthis code has been transmitted relay FIR will release to initiateanother code in which Wire I39 also is 9 Y venergized, so 'that theindication apparatus at the oiiice'will 'be controlled to `reilect thechange of *position'of the switch at `the station while maintaining thedisplayofthe carrier current indica- 'ltion without change.

1The operations previously described are those `normally-obtaining inthe system and are effected when line conditions are such that each ofthe #various indication-codes can be transmitted without'loss 'of :anycode due lto the inability to trans- :mit hecause ofthe line being'utilized for other 'code transmission. It sometimes 'happens,'how ever,that when a change in condition of apparatus a't a particular stationoccurs, the line is then in use under the control of a superior station,and .in such event when the starting relay at Ythe Vparticular stationis operated, it remains in ,its voperated 4position until that stationgains Aaccess 'to the vline and can transmit its indica- .tlons. LInsuch cases it vsometimes happens that when `a switch kat a station iscontrolled from one tposition toanother, the starting relay at thestationoperates to condition the station to transmit-anode, but the linecannot be obtained during the time that the switch is in transit andboth` .the ,normal and reverse switch indication relays HWP-and RWP arereleased to deenergize both of the switch indication channel wires E39and JM atthat station, and that the line is made available only afterthe switch has completed its Vvmovement and is locked in its newposition where the corresponding switch indication relay is picked 11ptoapply energy to the station terminal of the corresponding switchindication channel of the code. In such event, therefore, the movement`of the switch will of course be registered at :the Yoiilce, but thein-transit code which normally Visprovided will be omitted and theindication at the office will then change directly from one positionofthe switch to the other without the'usua'l intervening in-transiindication. Inconditions such as these where the in-transit. switchindication is omitted, the apparatus embodying :my invention operatesito effect proper control over the switch indications and carrierindications, yin Aa manner .which I shall now explain in detail, itbeing assumed that with vthe switch W in in its .reverse position soA.that relav'RWP lat the station is picked un, and so that relay RW Kand indication. lamps RV/'Hand .ICCK at the ofce vare zenergized. theoperator establishes-a control over fthe station apparatus and causeslswitch W -to restore to its normal position but line conditions preventthe transmission of a code from-the staition during the time the switchis unlocked and moving to its normal position. Thus, although urelay RWPreleases as soon as the switch is unlocked for movement, and relay RWPshifts `its contact 4 in the circuit of relay ST so that relayS'Ipperates to close its contact I4 in its operated 'or right-handposition lto condition the apparatus for transmission of a code, thecode is held offny'line conditions until after the switch operates to`and fbecomes locked in its normalposition 'where relay NWP becomesenergized and picks up. With the code held off, relay ST is retained inits operated position and relay FIR, which picked up when'both relaysNWP and `RWI were released with the Iswitch in transit, is 'heldenergized Yin its stick circuit completed when relay'NWPclosed itsfront'contact V{6,this stick circuitextending from termi-nal '-B4through l'con- .1.4 l'offrelay 'STinits operated position, front `10back contact "I1 of relay RWP, front contact I 5 of relay RPP andthewinding of relay FIR to 'terminal C.

lThis condition of 'the Aapparatus will obtain until such 4time as 'theequipment at the station can seize 'the communication line and transmit,the indication code. At the end o'f .the station selecting portion o'fthis code, relay ST will restore andrin'terrnpt the stick circuit ofrelay FIR, but the 'latter relay .will'hold up due to its slow releasingcharacteristics until after the complete code has been transmitted kandregistered. In this code, terminal Bat contact 8 of relay NWP will beconnected to .wire I 39 with -the result that .terminal ,1B at the.office will `be connected lto wire `Mlat a time when .relay RWK ispicked up, Yconsequently relay AOIR will pick up over a circuit ,whichmay .be .traced from terminal .49 through back contact 35fofrelay NWK,front contact 36 of relay vRWK and winding 31 of relay OIR to `termi--nal 1C. .Relay ,OIR thereupon closes its front contact 3ll-togpreparevits stick circuit-overfront con- --tact29 of :relay cD `when that relaypicks up, and

also closes its lfront contact :38 so that when relay D does pickup,relay -CHK becomes energized bya-circnit pathconnected in multiple with-winding ,31 Vof relay OIR `and including front contact 38 of .relayOIR, back contact 39 of relay vCI-IK, front lcontact Vlll -of :relay Dand 'the Winding of relay Theenergization vof relay .CI-IK is Yeffectedonly momentarily, however, since when relay :D gp'icks `lup it Iopens:.atrits `'back contact 32 the stick circuit of frelay RWK, and withterminal :5| :at the :office v.deenergized, relay '.RWK Yis likewise-deenergizediandreleasesto open its front contact 3'6 i'n'the circuitsof relay y'OIR and CI-IK. Relay CHKtisaproportionediwith slow pickupcharacteristics-suchfthat it will not pick up inthe relatively :shortinterval Aof time that it is energized underpfthe :conditions assumed.Inasmuch` as'back contact :25 of Arelay RWK is included in the pickupicircuitfo'f relay'NWK, the latter relay remains released until relay"-RWK releases to close its back contact '25, whereupon relay `N'WKpicks up becauseterminalBi-is connected to wire 49. The release 'of'.relayRWP results tin deenergizing lamp RWE, while'lamp' -NWEis'lightedwhenrelay NWK picks up. 'Then when relay-D releases, relay NWK is held-up over its stick circuit, and relayOIR releases. i

After the complete indication code hasbeen transmitted from 'the stationand registered at the office, relay FIR will release at the station toshift the position of fits .contact and cause Arelay ST to operate toinitiate another indication code. This indication finds terminal B atfront contact 8 yofrelayfNWP,connected to wire 39 so Ythat terminal B at`the ,office will be connected vto wire 49. When 'relay "D picks up,therefore, relay NWK will"be'held"up andthe apparatusat the oiiice willhold relay 'NWK energized lin its `stick circuit after Vrelay Dreleases.

Under/'the conditions justdescribed, it is apparent that the `apparatusfunctions to change vthe indications udisplayed by the switch indicationlamps, while'maintaining Without change the display of the `carrieriunit indication, in the case where=the-switchposition:is changed and nointransit` indication isprovided to the oice. Itis,

' o`f course,'obviousithatthe apparatus Will'function in 1acorrespondingly 'similar manner ,to register the change Vor switchposition -from normal to reverse,#Whilernalntainingthe display of thecar.- rier unit indication, 'in Athe event that the in- 1 1 transitindication is missedwhen the switch is moving from its normal to itsreverse position.

If now, with switch W in its normal position and this conditionregistered at the ofce by the energization of relay NWK and lamp NWE,the operator reverses the position of relay CH so that contact IS in itsright-hand position selects carrier unit 2CCU, the shift of position ofcontact 'l Will cause relay ST to operate and its vcontact I4 to closein its right-hand position to initiate transmission of an indicationcode, In this case, terminal B at contact 8 of relay NWP is connected towire |39, While terminal B is connected to wire |4| over the circuitcompleted through contact Il? of relay CH in its right-hand position,back contact of relay FIR, front contact I2 of relay NWP and backcontact 9 of relay RWP. It should be noted that if switch W had been inits reverse position when relay CH was reversed, then with relay RWPpicked up to connect terminal B at front contact 9 to wire |4|, theother wire |39 would also be energized over back contact 3 of relay NWP,front contact I3 of relay RWP, back contact I| of relay FIR and contact|i of relay CH in its reverse or right-hand position. It fol lows thatwhen a code is initiated from the station by reversing relay CH, bothterminals |39 and I4I will be energized, one being connected to terminalB at a front contact of the switch indication relay that is energizedand repeats the position of the switch, and the other being connected toterminal B at contact I of relay CH.

At the office, both terminals 49 and 5| will be energized so that beforerelay D picks up, relay OIR picks up over its circuit from terminalthrough back contact 4| of relay RWK, front contact 42 of relay NWK andwinding 31 of relay OIR. Relay OIR closes its front contact 3|! toprepare its stick circuit and its front contact 38 to prepare thecircuit for relay CI-IK that is completed, in multiple with winding 31of relay OIR, when relay D picks up to complete a path including Yfrontcontact 38 of relay OIR, back contact 39 of relay CHK, front contact400i relay D and the winding of relay CHK. picks up and operates itsmake-before-break contact 39 from its back to its front position, inwhich another circuit is completed for relay CHK, extending fromterminal 49 through front contact 35 of relay NWK, front contact 43front contact 39 of relay CHK, front contact 40 of relay D and thewinding of relay CHK. Relay CHK of course operates its contact 24 awayfrom its back point to deenergize lamp ICCK, and contact 24 closes toits front point to energize lamp ZCCK, thereby to indicate the selectionof unit ZCCU at the station.

When relay D picked up, relay NWK was held energized with energy appliedto terminal 4S, and relay NWK held open its back contact 3| in thecircuit of relay RWK so as to maintain -that relay released despite theapplication of energy to its terminal 5|. Then when relay D releases,relay NWK is held energized over its stick circuit, while relay CHK islikewise held energized in its stick circuit including its own frontcontact 44 and back contact 4|) of relay D. The indication lamps NWE andZCCK therefore are maintained energized to indicate that switch W isnormal and relay CH is reversed.

The apparatus at the office is arranged to main tain relay CHK energizedWithout change by indication codes received from the station until acode is received which includes steps indicating Vhat relay CH has beenrestored to its normal Relay CHK thereupon of relay OIR, I

position. For example, if with relay CH in its reverse position theoperator controls switch mechanism SM to operate switch W to its reverseposition, relay NWP will release as soon as the switch unlocks, andrelay NWP will close its back contact It tofpick up relay FIR, and willshift its contact 3 to cause relay ST to operate and initiate a code.During this code back contact Il of relay FIR will be held open, andboth wires |39 and I4| will be deenergized, so that at the oliice relayNWK will release when relay D picks Aup. The release of relay NWKdeenergizes lamp NWE to signify that switch W is in tra'ffisit betweeneX- treme positions, and Valso results in closing back contact 26 ofrelay NWK to complete a circuit for relay OIR, which circuitincludeshack contacts 23 and 2 of relays NWK and RWK, respectively, andwinding of relay OIR, so that relay OIR picks up. Relay NWH also .closesits back contact 35 when it releases, tc complete a circuit includingthat contact, back contact 46 of relay RWK, iront contact 3Q of relayCHK, front contact 48 of relay D and the winding of relay CHK, so thateven though the stick circuit of relay CHK is opened when relay D picksup, relay CHK is held energized during the time thatrelay D is held up,over a circuit completed whenboth relays NWK and RWK are released. RelayCHK is of course held energized in its stick circuit when relay Dreleases, and relay CHK maintainsv the display of lamp ZCCK. v g Y Whenswitch W at the station is locked in its reverse position, relay RWPpicks up to shift the position of its contact '4 and therefore operaterelay ST to start an indication code. Contact I4 of relay ST in itsrreverse position also completes the stick circuit for relay FIR, throughits own front contact I8 vand front contact I1 of vrelay RWP, and relayFIR accordingly is held energized during this Vcode until relay STrestores at the end of the station selecting'portion of the code, withthe relay FIR being held up for the remainder of the code by its slowreleasing Vfeatures. During this code, therefore, contact II of relayFIR is'held open to isolate terminal' B at Contact i0 of relay CHfrom'the wires |39 and |4|, and in this code the wire |4| is'energizedby terminal B at front Contact 9 of relay RWP. This results in theenergization of terminal 5i at the oiice, and when relay D picks up,relay RWK also picks up to close its front contact 33 and energize lampRWE to signifythat switch W is in its reverse position. Relay OIR, whichwas held energized over back contacts of relays NWK and RWK until relayRWK picked up, is now held energized in its stick circuit completed overfront contact 2S of relay D, and relay CHK is now held energized'overfront contact 4| of relay RWK, front contact 43 of relay OIR, front con#tact 39 of relay CHK, front contact le of relay D and the winding ofrelay CHK. When relay D releases, relay RWK is held energized' over itsstick circuit including back contact 32 .of relay D; relay CHK also isheld energized in its stick circuit completed over back contact 40 ofrelay D; while relay OIR releases. It follows; there fore, that relayRWK at the office is picked up to establish the reverse switchindication at the office, while the display ofY the reverse carriercurrent indication is maintained; Y

At the end of the slow release period of relay FIR, its back contact IIcloses and contact 5 is operated to cause relay ST to reverse andinitiate another code. In this code both wires |39 and 4| are energized,wire 4| overjfront Contact!! :of relay RWI?, and wire V1:39 over Joackcontact f8 .of yrelay NWP, iront contact Ii3 of relay RWP, zbackcontact-.I I of relay -FIR and reverse contact Hifof relay CH. At .the zofhce,therefore, both Avirescil -andS-I are energized so that `with relayj:HWK,picked up, relay OIR y,picks up` over the circuit from terminal 49.through back contact 35 @ofrelay `iront ycon-tact 35 of relay RWK .and-w-indingf31 Vof relay OIR.. When relay D .subsequently vpicks up 'toopen the stick circuits of relays RWK and CH-K, relay RWK is heldenergized .over its pickup circuit including back .gized yover its stickcircuit including front contact 29 of relay D. vAt the release of relayD, relay :OI-R. also releases but relays RWK and CHK .remain picked upin their stick circuits.

-If the operator should reverse relay CH under ,the conditions assumed,contact I9 Yof relay CH will .of course operate :select unit ICCU, andthe shift of contact 1 .resultsrinoperation of .relay ST to initiate acode, .in -whiclr terminal B at .front contact 9 of relay .RWP isconnected to wire I4I. When relayD picks upat the ofce, vto open f:orprelays RWK Vand CHK, relay RWK will be heldenergized in its pickupcircuit Asince terminal ,B is 'connected at this time to wire 5I,butrelay iCHK'will release to open its front contact 24 'to Ide'energizelamp ZCCK.r The other vlamp will, however, he energized over contact 24of .relay -CHK inits `hack position, to indicate that relay CH is in itsnormal position 'at'the station where it selects carrier unit ICCU. Atthe Vrelease-of relay D, relay RWK will beheld energized .1

in its stickcircuit while relay CHK will remain released, andconsequently the apparatus will .function to maintain the display ofl'the switch zindication :at ytheoiice'vvhile altering the display:ofthe carrier unit indication to accord with a change in selection oflunitsv at Nthe station.

The system arrangement involving lcontact 5 of .relay FIRinthe'stickAcirc t of startingrelayST which assures the transmission from thestation .ofi two indication codes each freaches and is Vlocked'in itsextreme position iollowing a .change of position of the switch, is ofparticular advantage inthe case where the oper- `ator effects :a changein the positions of both zswitch W iand of changeover relay CH. That-isto say, if with the switch W and 'relay CH both 'reversed Iand relays'RWK vand CHK held enera'gized at 'the olii-ce to :indicate 4thiscondition, la contrczrl from-the oicecauses switch W and relay .CHitooperate to their respective normal posiitions, .the riirst indicationtransmitted following theashift 'in `positionof relays RWP and CH `findsbothterminals `['39 and `HH deenergized, and as .a :result relay RWKwill be released Atc rcausethe in-transl? indication time. Relay OIR,will he picked :up 'with both relays NWK and RWK released :to closetheir fback :contacts 2.6 and `21 respectively, .and i-relay iCHK willbe .held energized over 4its :circuit .ineluding .its 15,5y 'and 46 of.relays :NWK and RWK, respectively. Then when rvswitch W .reaches andiis locked ein its normal position, relay :shifts .its position :to.operate .relay ST and the latter -irtiates another code, and.alsoholdsrelay EIR to its normal position to the `stick circuits timeswitch `W I..

front contact 39 and hack .contacts .l

not communicate with were-released) :energized in fitsstick. circuitThecode :initiated :by relay 4lNWP picking up v-iinds itcrrninal LB uatfront contact A8, of relay connected -to :terminal L39 .and :as 1.azresult relay .atthe-.oice picks up and closes :its front contact 23 fto:energize lampwNWE,1and `front Contact .-35 .to -hold v'relay `CHKenergized. :Relays NWKyand CHKre-main energized in their r:respectivestickcircuits when relayD at 'thefofce releases. After the transmissionoi 'this rst code, relay FIR will release to voperate `relay ST andiinit-iate Vthe second code. This .also finds terminal B at frontcontact 8 oi'relay NWP confnected .to terminal YI 39 yand as a resultrelay NWK is :held energized when relay D picks up at the office. Relay'OIR .is now deenergized so :that Vwhenthe 'stick circuit of relay CHKis broken :by relay AD picking-up,1relay CHKais deenergized and releasesto cause :lamp ICCK '.to become `lighted, .and vlamp 2CCK to :beextinguished. Then when 'relay D releases, :relay NWK :is l.held up andthe -oflceindicates 'that .switch W and relay CH fare 'in their:respective normal positions.

- 'It :should :be--notedthat relay yCII-IK is controlled by thesecond.indication `transmitted in this case, andthat only where thesecondindication is the same as 'the irst `will .relay CHK be vreleaseditis :energized at the office. The transmission .of Ytwo :indicationsYone .reflecting the 'position :of the track switch 4and ith-e otherreflecting the position ;oi".relay-.CH`isadvantageoustfollowingeachmovement ofthe switch into an extreme position:in A'order to afford. `information relating tto both the switch andchangeover relay. This arrangement is therefore `to be preferred overthat shown in Fig. la' and 'hereinafter described, in which .the secondindication is provided only if Arelay CH is reversed.

The system arrangement also provides for en- .ergizingrelay FIR wheneverthe station disconnect relay RPPlisreleased and closes yits back`contact 5|5. fAs pointed out in Jackel Patent 2,411,- BFT5, when relayRPP' is released the station canthe onicebut theoice can lcommunicatewith Athe station. If during 2the period that relay RPP is released,the'position-of switch Whas been changed, then'relay ST 'will y.he finits Aoperated position where it remains Yuntil relay IRPPis picked 4upand an indication code is transmitted to the oflice. When relay RPPpicks up, its 'liront contact I5 closes to'complete the stick circuit ofrelay FIR closed through contact |24 of relay 'ST in 4its operatedposition, consequently the 'first-code transmitted after relay RPP picksup will reflect the position-of 'switch`W, and after that code `"has/been'received and registered a't I-theoffice, relay YJFIR. will releaseto initiate vthe second code in which the position ofrelay CH will bereflected. Controlling relay FIR'by relay RPP .inthis .manner thereforepermits review of `both .-7.5 and is retained in tits ,picked -np .layOIR at .the office.

switch W and irelay CHafter the :station equipment is restored toservice by ypicking up relay RPP.

`lrorn zthe uforegoing it is readily apparent 4`that I vhave provided-asystem in which atwo-position device at .a station can `loe indicated atan oidce over the two Y.steps Yused to indicate the 'position of fathree-position device 'at the station. The system is arranged to employan intermediate relay 'FIRat the :station .and an .intermediate 're- The.field ystation intermecliate .relay is energized 4Whenever the:threeposition device occupies its intermediate :position position afterthe station transmits the code indicating A that the device has reachedand occupies its eX- treme position. If the field station intermediaterelay is released when a code is transmitted from the station, itconditions the code under certain conditions to include stepscorresponding to the energi'zation of both terminals of the switch stepsand consequently provides a fourth indication by use of these two steps,the determination of whether the fourth indication is or is nottransmitted when relay FIR is released, being made by the position ofthe two-position device with which the fourth indication is associated.

The oiiice station intermediate relay OIR is energized whenever bothswitch indication relays at the oiiice are released, or whenever witheither switch indication relay picked up a code is received whichresults in the energization ofthe channel for the other (i. e.A thereleased) indication relay. The oiiice intermediate relay functions tocontrol an additional relay provided at the oice to indicate thetwo-position device at the station, with the intermediate relay at theoilice controlling the additional indication relay so as to effect itsenergization when the fourth indication, e. g. both switch stepsenergized, is received at the oiice, and arranged to maintain theenergization of the additional indication relay until with relay FIRreleased at the station, a code is received which contains only oneenergized switch step. It follows that by use of the intermediate relaysFIR and OIR at the station and oiiice respectively, in addition to thenecessary indication and repeating relays provided at both the oiiiceand station, a system is provided which indicates over the two switchsteps of a code, not only the three-position switch, but also atwo-position device, with the indications of either of the two devicesbeing maintained without change upon receipt of codes indicating a.change in position of the other of such devices.

In the system heretofore described, the eld stationY intermediate relayFIR is represented with its contact interposed directly in the stickcircuit of relay ST, so that whenever the position of switch W shiftsfrom either extreme position to the other, two indication codes aretransmitted to the station after the switch reaches and is locked in itsother extreme position. Of these, the rst indicates the locked positionof the switch and the second is initiated when relay FIR releases sothat in this second code only one, or both, of the switch indicationchannels at the station will be energized dependent upon whether thetwo-position device is in its normal or reverse position, respectively.A slight modification of the system of Fig. 1 is represented in Fig. 1awhich shows the stick circuit of relay ST arranged to include contact 5of relay FIR only when relay CH is in its operated position where itscontact 1 will be in its right-hand position to interpose Contact 5 ofrelay FIR in the circuit of relay CH. It follows that if the circuit ofFig. 1a were substituted for the circuit of relay ST shown in Fig. 1,then although relay FIR would be picked up and released during theoperation of the apparatus at the station in exactly the same manner ashas been pointed out hereinbefore, the relay FIR would not control theoperation of relay ST unless relay CH is in its operated position, andtherefore after the operation of the switch from one extreme position tothe other, one indication code will be transmitted to the oiiice ifrelay CH is in its normal position, with two indication codes beingtransmitted only `16 in the case where relay CH is in its operatedposition. The alternative arrangement shown in Fig. la therefore has theadvantage ofrequiring the transmission of the second successive codefrom thestation only when relay CH is positioned to provide the secondcode with steps conveying the fourth indication, e. g. both switch stepslong.

Although I have herein shown and described only two forms of remotecontrol apparatus embodying my invention, it is understood that variouschanges and modifications may be made therein within the scope of theappended claims without departing from the spirit and scope of myinvention.

Having thus described my invention, what I claim is: Y

l. In a centralized traflic control system of the type described forrailroads, the combination with an olice and a station and acommunication system linking said oiiice and station, said stationprovided with a first device having two extreme positions and anintermediate position and with a second device having a normal and anoperated position, said communication system provided with two channelsover which code elements having one character or another may betransmitted and including a station starting relay having a normal andan operated position in the latter of which it initiates transmission ofcode elements over said channels, said system including means controlledby said rst device in response to a movement into or out of eithercxtreme position and by said second device in response to a shift in itsposition for causing operation of said starting relay to initiate thetransmission of code elements over said channels, means governed by saidiirst device for controlling said communication system so that one orthe other or both of the code elements transmitted over said channelshave said one character depending upon whether said rst device is in oneor the other of its eXtreme positions or is in its intermediateposition, of means governed by said second device for controlling saidcommunication system so that the code elements transmitted over saidchannels both have said other character when said second device is inits operated position, and means governed by said rst device renderedeffective whenever said iirst device occupies its intermediate positionfor establishing the transmission of two sets of code elements when saidrst device subsequently moves into an eXtreme position, with characterof the rst set of code elements controlled by said first device and thatof said second set controlled by said second device.

2. In a centralized traffic control system for railroads, thecombination with an oiiice and a station and a communication systemlinking said ofiice and station, said station provided with a firstdevice having two extreme positions and an intermediate position andwith a second ldevice having a normal and an operated position, saidcommunication system provided with two channels over which code elementshaving one character or another may be transmitted and including astation starting relay having a normal and an operated position in thelatter of which it initiates transmission of code elements over saidchannels, means governed by said rst device for controlling saidcommunication system so that one or the other or both of the codeelements transmitted over said channels have said one characterdepending upon whether said first device is in one or the other of itsextreme positions starting .relaytooperate and; initiate the trans-fA iomission of code i over saidy channels, means` govf erned by saidstarting relay and by saidAA rst device for;controlling said other.relay: so th atv whenever saidiirst device moves efrom its inter.mediatepositionintoeither extreme position the 15 transnjlission` of thecode elements initiated thereby.is followed by as hift in position ofsaidy other relay, wherebyv saidsystem is caused toi transmit twosuccessive; groups of code elements; over said channelsvrwhenever saidrst device.- 20

moves into either extremelposltion, and meansgoverned by saidcther.relay for controllingvsaid. communication-system so ithat thecha'racteroffA the codeeeleme `tstransmitted-in.the rst groupisgcontrolled bysaidrst device and that of theA g5 second group iscontrolled bysaid second device.

3.- In aicentralizedtraflio control system of the: type described forrailroads, the combination with anoice and astation anda communicationsys-l tem link-ing; said onice and station, said stationV 39 providedwith a first .device'having two extreme. positions-and an intermediateposition and with a second device havinga normal and an operated.position, said communication system. provided with two channels overwhich code elements hav-V 3;, ing-onecharacter oranother may betransmitted, l said `,communication system provided with a stationstarting relayhavinganormal and an oper-y ated position in the latter ofwhich it initiates transmissionof codeelements over said c han.-A 40nels, means governed by said first device for controlling saidcommunication system so that; one .or the. other or both of the codeelements transmit^ed over: said channels have said one. characterdependingI upon whether said first de.- vice is in one or the .other ofits two extreme positions or is; inV its intermediate position,4 ofganother relay,` means governed bysaid liirst devicer and by said-otherrelay, in response toashift: of posi-tion of that rst device or other`relay for ,50 causing lsaid starting relay-to operate and initiate the.-transmission of. codeV over said channels, means gover-ned'byl saidstarting relayand by said first device for controllingsaid otherrelayfzso; that if-said second.` device is in itsoperatedl positionwheneverqsaidrstdevice moves-intim eithertextreme positionzthetransmission of theg code elements initiated thereby; is followed by ashift in position-o .saidg other; relay, whereby-,.-- said systemy iscaused. to groups of code elements-oversaid channels whene ever saidrstdevice-.movesinto either eXtremeposition,l and means governed by saidother relayforv controlling said communication system so thatthe codeelements transmitted in theseconde group both i havev saidotheri:character, the. characteroi. the codev elements in-the first group=bgeingzcontrolledrby said first devicer Li; In a remote con-trolsystem,` the combinationv with an oiiice anda station and a systemlinking said oice: andstation, saidstae. tion providedl withzarstdevicehaving two eri-.-V treme positionsgand an-.intermediate position .andwith a lsecond devicehaving anormal .and am operated position, saidcommunicationsystcrrr` 75;,

" system. linking saidfoiii'c e`andv station;

' 09de'. 'elements aver.

.-transmittwo successivefi)V communication.; 7:01

18l providedwithtwo; channelslover which code elements having;A on e cliaracterv or;` another may be` transmitted iand includingatstationstartingrelay' having, anormaland an operated' position in" the latter of.; whiclnity initiates transmission' of code elementsoversaidfchannels, said systemincludingimeans controlled lby said-inist'device in responsegto airnoveinentinto .o r outofeither ex-l treme-posion and by-said second'dvic'e in re; spense -toa shiftofposition forcausingoperationmfmsaid;startingrelay to initiate the transmission o fcode.y elements over said channels, means governed by. said AfirstdeviceA for controle lingsaidl. communication system so that'thecode"element transmittedfover. one vof said' channels"has;saidlone;characterY or the other depending uponflwhether. ornotsaid'iirst device is in one ofJ its;egitremepositionsandthe codeelement'transe mittedover theoth Mr of said channels has saidNh one.;character or.v the .other depending upon` Whether onnot saidfistdevi'ceis in'the'other of its extreme positionsandboth saidcode'eleementsfhavesaid other'. character if saidrst de'- V- iceg is;its said intermediate position', of another relay! meansgoverned .bysaid 'other relay in response to. a shift of "position of that relayfor, causing: saidstartingfrelay to operate'and'initiatetheftransmissinof cod over'said channels,means; goyerne'dlby saistarting relayand by; saidv first device, for controlling 'said othervrelay so that. whenever sa'idfr'st' device moves'l intoyeither.` extremeposition the transmission of thecode elemen tsinitiate,djtherebyA isfollowed by a; shift in. position .of said otherV relay,A whereby i said4system isgcausedt'o. transmit twoV successive* groupsofcodeelementsoyersaid' channels whenever said first deyice ..moves Lintoieitherextreme position, andmean'sxgoverne'dQ by said seconddeviceforicontrollingsai'd communication system 'so that thecode ,elementscaused" to betransrnittedL in tresponse :tof a shift 'of position ofsaid other1 relaytbothhave saidOne character if said 'secondi device.isfin. its `said.joperatedjposition.

5,. Inairemoteconticlsystem; the combinationA with an otieandfastationand a communication Y* said sta-v tion provided-lwith a'rst devicehaving rtwo ex`- treme positions'A and an intermediate positionland-.withga secondfdeyice havinga normal and' an operated-positidin;said communication systemI provided Vwith twochannels'joy/erwhich code 'ele transmitted andincludingr aV station' starting relay;having..a` normal" andan' operated position g in .tl'ie.lattergowhielffitji jates transmission of*-` 'said channels; said system gixicliidirigv means controlldjjby saidrst device inresnonseto amovement'ginto or. out of either" extreme position an'djbysaid'seconddevice inV response *tol any, shifti in itsposition forcausing'V operation, of saidstarting, relay; to initiate thetransmission oi codjele'ments over saidchannels;y saidlsystem ,alsof.'ncludinggmeansjfor controlling saidf,commnnicatiri ,system by. saidrst device; so ,that:thecode elementtransmitted over one of saidchannelshas said )onecharacter or the other depending uponlwhether ornot'said rstv device isinQOne;of.itsrexi;reme positions and/the code;element .transmittedfoverl.therother-of said channels-hassaideoneicaracter;or..the other depend. ingyuponvrhether.orfnot .said .firstdevice is in the.

` other of itsiextreme .positions and .both said .code

elements have. said other characterif saidrst.:

deyiceisffin itsQ.saidintermediate` position, said system-falso..havingA means. governed by said encased second device provided thatdevice occupies its said operated position for controlling saidcommunication system so that both code elements transmitted have saidone character, of another relay, means governed by said other relay inresponse to a shift of position of that relayfor causing said startingrelay to operate and initiate the transmission of code over saidchannels, means governed by said starting relay and by said rst devicefor controlling said other relay so that whenever said first devicemoves into either extreme position the transmission of the code elementsinitiated thereby is followed bye shift in position of said other relay,whereby said system is caused to transmit two successive groups o1' codeelements over said channels whenever said iirst device moves into eitherextreme position, the character of the code elements of the first groupgoverned by said rst device and the character of the code elements ofthe second group governed by said second device if 1t is then in itsoperated position.

6. In a remote control system, the combination with an oilice and astation and a communication system linking said cnice and station, saidsta-Y tion provided with a first device having two extreme positions andan intermediate position and with a second device having a normal and anoperated position, said communication system provided with two channelsover which code elements having one character or another maybetransmitted and including a station starting relay having a normal andan operated position in the latter of which it initiates transmission.of code elements over said channels, said system including meanscontrolled by said first device in response to a movement into or out ofeither extreme position and by said second device in response to anyshift in its position for causing operation of said starting relay toinitiate the transmission of code elements over said channels, saidsystem also including means for lcontrolling said communication systemby said first device so that the code element transmitted over one ofsaid channels has said one character or the other depending upon whetheror not said rst device is in one of its extreme positions and the codeelement transmitted over the other of said channels has said onecharacter or the other depending upon whether or not said rst device isin the other of its extreme positions and both said code elements havesaid other character if said rst device is in its said intermediateposition, said system also having means governed by said second deviceprovided that device occupies its said operated position for controllingsaid communication system so that both code elements transmitted havesaid one character, of another relay, means governed by said startingrelay and by said rst device for controlling said other relay so thatwhenever said rst device moves into either extreme position thetransmission of the code elements initiated thereby is followed by ashift in position of said other relay, means governed by said otherrelay in response to a shift of position of that relay provided saidsecond device is in its operated position for causing said startingrelay to operate and initiate the transmission of code over saidchannels, whereby said system is caused to transmit two successivegroups of code elements over said channels whenever said first devicemoves into either extreme position when said second device is in itsoperated position, the character of the code elements of the rst groupgoverned by said said channels,

*a nels over which code code element transmitted over 20 nrst device andthe character of the code eleA ments of the second group governed bysaid second devicei 7. In a remote control system, the combination withan office and a station and a communication system linking said oice andstation, said station Yprovided with a plurality of elements including adevice having two extreme positions and an intermediate position, andsaid communication system provided with two channels over which codeelements having one character or another may be transmitted andincluding a station starting relay having a normal and an operatedposition in the latter of which it initiates transmission of codeelements over said channels, of another relay, a pickup circuit for saidother relay completed when said device is in its intermediate position,a stick circuit for said other relay completed over a front contact ofthat relay when said starting relay is in its operated position and saiddevice is in either of its extreme positions, means for controlling saidstarting relay to cause it to operate to its said operated position upona change in position of any of said plurality of elements or said otherrelay, means for controlling said communication system b-y said deviceso that the code element transmitted over said one channel has said onecharacter or the other depending upon whether or not said device is inone of its extreme positions and the code element transmitted over theother channel has said one character or the other depending upon whetheror not said device is in the other of its extreme positions, and meanseffective at times if said other relay is released for controlling saidcommunication system so that the code elements transmitted over bothsaid channels have said one character.

8. In a remote control system, the combination with an oice and astation and a communication system linking said oiice and station, saidstation provided with a device having two extreme positions and anintermediate position, and said communication System provided with twochanelements having o-ne character or another may be transmitted andincluding a station starting relay having a normal and an operatedposition in the latter of which it initiates transmission of codeelements over of another relay, a pickup circuit for said other relaycompleted when said device is in its intermediate position, a stickcircuit for said other relay completed over a front contact of thatrelay when said starting relay is in its operated position and saiddevice is in either of its extreme positions, means for controlling saidstarting relay to cause it to operate to its said operated position upona change in position of said device or said other relay, means forcontrolling said communication system by said device so that the codeelement said one channel has said one character or the other dependingupon whether or not said device is in one of its extreme positions andthe the other channel has said one character or the other depending uponwhether or not said device is in the other of its extreme positions,means effective at times if said other relay is released forcontransmitted over trolling said communication system so that the codeelements transmitted over both said channels have said one character,and means at said oice selectively responsive to the character of thecode elements transmitted over said two channels.

oifice andstation, said firstv device having two an intermediate,position and with a. second device having a normal and an operatedposition,. and said. communication syS- tem provided with two channels.over. which. code. elements; having one. char-.acier oranother may he;transmitted and including a station` startingl relay having a normal.and an operated position in the latter ofi which it` initiatestransmission or code elements over said channels, of. another relay, apickup circuit for said, other relaycompleted. when. said, rst device.is in its intermediat-e` position,r a stick circuit-ion said other relaycom-w plated over av front contact. ofk that. relay when said starting.relay` is:- in its. operated position and said rst device is in eitherofits. extreme posi.V tions, means for controlling said starting relayto cause it tov operate tov its said operatedposi?. tion upon a change.in position of said firstv or second device or said other relay, means`for controlling said communication system' by: said first devicev sothat the code element transmitted' over said one channel has said onecharacter or the other depending upon whether or not said nrstdevicefisy in. one of. its extreme positions and the c ode elementtransmitted over the other channel has said onepcharacter or the otherdependingupon Whether or not said first device is in the other of itsextreme. positions, and means governed by said second. device in itsoperated position eiective if said otherv relay'v is released forcontrolling. said communieationy system so 'that the code elementstransmitted over both said channels have said one character,

10.I Ina remote ccntrolsystem, the combination with an pince and a;station and a corn.- munication system linking saidoice and station,said station provided with aiirst device having` two extreme positionsandan intermediate position and with a second device having a normal andan operated position, and said communication systemV provided with twochannels over which code elementsl having one character or another maybe transmitted and including a station starting relayhaving a normal andan` operated position` in the latter'ofV which it initiatestransmissionoi code elements over said channels,` of anintermediate'relay, a station disconnect relay, a pickup circuit f orsaidintermediate relay completed when said-,station disconnect relay isreleased,A a second pickup circuit for said intermediate relaycompletedover a front contact of said station disconnect relay' wheneverksaid 'first device is in its intermedlateposition, a stick circuit forsaid intermediate relay completed over a front contact ofA that relayand a iront contact of saidy station disconnect relay. when saidstarting relay is in its operated positionvand saidrst device is ineither of itsfextremepositions, means for controlling said startingrelay to cause it to operate to its said operated; position upon achange in position lof said rst or secondv device or said intermediaterelay, 'means for controlling said communication system by said -i'irstdevice so that the .code element ltransmitted over said one channel .hassaidonecharacter or the other depending 7upon whether or notrsaid` firstdevice is in one of its extreme positions and the `codeelement'transmitted vov er theother channel has said. oneL .character.or the l.other depending upon whether or not .said first: device isinthe otherl of: its. extreme positions, and means governed lby saidsecond device operated position tive-if said intermediate ralentisreleased icrfcone trolling' said comm tion; sys-.tern so that. the code:elements: trans over; both. chairA nels have said one charenton 1.1.A Inaremote control System, thcccmlcinationr with. monica and a; station anda communication. system linking: said cnice and station. and proa 1 .0;channels: over which code. clef.. ments.; having one; character: or;another may :f transmitted-,said stat-,ion pravidcda Withmcans: foncontrolling the character: of the. 'code/.elements transmitted over saidchannels; of; two.L indication. relays. at said office, one,` for eachchannel,a a, sich: up circuitforeach. indication relay supplied; with.energy only when a code elementiof; saidA one;l character istransm'ttedover'the associated chan: nel and including aback, contact oftheotherfijdication relay., a stick. circuit: eiective ii'an indi-r. cation relayis.. picked up by a code element. or said one charactentransmitted over.its associated channel to. maintain that; relay picked 119.-. until;Acode elements; are. subsequently transmitted over. said. channels,indication means: at. said office .Y selectively controlled by saidftvvoindication relays, another relay atsaidofiicaarst circuit. iorlpicke.ing up said other relay completed whenfboth saidy indication relays.are. released; a second circuit. for picking up said other relayscompleted when a code element of saidone.` character is transev mittedover one of said channels. and' the. indica@ tion relay associated with.the other of; said chane. nels is picked up, and additional: indicationmeans; at said oflice selectively controlled. by said. twol indicationrelays and by. said other relay.

12. In a remote con-trol system, the combines. tion with an oiiice'andvastation and a comm-unica-n tion system linking said cnice and; stationand. providedwith two channels over which code ele:Av ments having. onecharacter orV another may. be transmitted, said station provided withmeansfor controlling the character of'. the code elements transmittedover said-channels, of two indication. relays at said office one foreach channel", a. picks up circuit for each indicationrelay' suppliedwith energy only whenv va. code element or said .one character istransmitted over the associated chan:` nel and including a back contactof the'v other indie cation relay, a stickvcircut effective if an indi:cation relay is picked up; by a code element of.' said one Acharactertransmitted: over its associated. channel to maintain that relay. pickedup until.: code elements. are subsequentlyl transmitted, over'. saidchannels, another relay at said office, a first circuit for pickingupsaid other relay completed. when both said indication relaysv .arereleased-,14 a second circuit for picking up( said other relay,completed if a code element .oilsaid one .character istransmitted over.one .ofrsaid channels when the indication relay associatedwfith theother of said'r channels. is picked up, a third indication .relay atsaid. office, a branch path .in said .second circuit including `a frontcontacter. said other relay-for; picking up said third indication relay,and ,at stick circuit effective if said thirdindication relay.y is`picked up over said loranchpath to hold ythat res. lay picked up until:code elementsv subsequently are received at .said oice.

'13'. In a centralized traffic .controlling system. for railroads, theVcombination with an. office and a station and a communication systemlinking-r said oflice and station and provided; with twoA channels. overwhich code .elements having one character or another may he transmitted,said; 75 station provided. with means. for controlling character of thecode elements transmitted over said channels, of two indication relaysat said oflice one for each channel, a pickup circuit for eachindication relay supplied with energy only when a code element of saidone character is transmitted over the associated channel and including aback contact of the other indication relay, a stick circuit eiective ifan indication relay is picked up by a code element of said one charactertransmitted over its associated channel to maintain that relay picked upuntil code elements are subsequently transmitted over said channels,another relay at said office, a iirst circuit for picking up said otherrelay completed when both said indication relays are released, a secondcircuit for picking up said other relay completed when a code element ofsaid one character is transmitted over one of said channels and theindication relay associated With the other of said channels is pickedup, a third indication relay at said cnice, a branch path in said secondcircuit including a front contact of said other relay for picking upsaid third indication relay, stick circuit means eiective if said thirdindication relay is picked up over said branch path to hold that relaypicked up until code elements subsequently are received at said oilice,additional stick circuit means for said third indication relay effectiveduring receipt ofcode elements if a code element of said one characteris received when the associated indication relay and said other relayare picked up, and another stick circuit means for said third indicationrelay effective when both indication relays are released.

14. In a centralized traihc controlling system for railroads,the'combination with an oiiice and a station and a communication systemlinking said oiice and station and provided with two channels over whichcode elements having one character or another may be transmitted, saidstation provided with means for controlling the character of the codeelements transmitted over said channels, of two indication relays atsaid oiice one for each channel, a pickup circuit for each indicationrelay supplied with energy only when a code element of said onecharacter is transmitted over the associated channel and including aback contact of the other indication relay, a stick circuit eiective ifan indication relay is picked up by a code element of said one charactertransmitted over its associated channel to maintain that relay picked upuntil code elements are subsequently transmitted over said channels,another relay at said cnice, a first circuit for picking up said otherrelay completed when both said indication relays are released, a secondcircuit for pickingr up said other relay completed when a code clementof said one character is transmitted over -'one of said channels and theindication relay associated with the other of said channels is pickedup, a third indication relay at said oice, a branch path in said secondcircuit completed when said lother relay picks up for picking up saidthird' indication relay, stick circuit means effective if said thirdindication relay is picked up over said branch path to hold that relaypicked up until code elements subsequently are received at said cnice,additional stick circuit means for said third indication relay effectiveduring receipt of code elements if a code element of said one characteris received when the associated indication relay and said other relayare picked up, another stick circuit means for said third indicationrelay effective when both indication relays are released, and indicationmeans selectively controlled by said two indication relays and otherindication means controlled by said third indication relay.

l5. In a centralized traic control system of the type described forrailroads, the combination with an omce and a station and acommunication system linking said oiice and station, said stationprovided with a first device having two extreme positions and anintermediate position and with a second device having a normal and anoperated position, said communication system provided with two channelsover said code elements having one character or another may betransmitted and including a station starting relay having a normal andan operated position in the latter of which it initiates transmission ofcode elements over said channels, said system including means controlledby said rst device in response to a movement into or out of eitherextreme position and by said second device in response to a shift in itsposition for causing operation of said starting relay to initiate thetransmission of code elements over said channels, means governed by saidiirst device for controlling said communication system so that one orthe other or both of the code elements transmitted over said channelshave said one character depending upon whether said rst device is in oneor the other of itsextreme positions or is in its intermediate position,of means governed by said second device for controlling saidcommunication system so that the code elements transmitted over saidchannels both have said other character When said second device is inits operated position, means governed by said iirst device renderedeffective whenever said iirst device occupies its intermediate positionfor establishing the transmission of two sets of code elements when saidfirst device subsequently moves into an extreme position, with thecharacter of the first set of code elements controlled by said firstdevice and that of said second set controlled by said second device, twoindication relays at said ofce one for each channel, a pickup circuitfor each indication relay supplied with energy only when a code elementof said one character the associated channel and lay is picked upcharacter transmitted over its associated channel to maintain that relaypicked upY until code elements are subsequentlyV transmitted over saidchannels, another relay at said office, a first circuit for picking upsaid other relay completed when both said indication relays arereleased, a second circuit for picking up said other relay completedwhen a code element of said one character is transmitted over one ofsaid channels and the indication relay associated with the other of saidchannels is picked up, a third indication relay at said oiiice, a branchpath in said second circuit including a front contact of said otherrelay ior picking up said third indication relay,

stick circuit means effective if said third indica- Y tion relay ispicked up over said branch path to hold that relay picked up until codeelements subsequently are received at said oce, additional stick circuitmeans for said effective during receipt of code elements if a codeelement of said one'character is received when the associated indicationrelay and said other relay are'picked up, and lanother stick circuitmeans for said third indication relay eiective when bothindicationrelays are released.

16. In a centralized traiiic control system of third indication relaythe type described for railroads, the combination with an ofiice and astation and a communication system `linking said oilce and station, saidstation provided with a rst device having two extreme positions and anintermediate position and with a second device having a normal and anoperated position, said communication system providedwith two channelsover which code elements having one character or another may betransmitted and including a station starting relay having a normal andan operated position in the latter of which it initiates transmission ofcode elements over said channels, said system including means controlledby said first device in response to a movement into or out of eitherextreme pos'tion and by said second device in response to a shift in itsposition for causing operation of said starting relay to initiate thetransmission of code elements over said channels, means governed by saidrst device for controlling said f communication system so that one orthe other or both of the code elements transmitted overl, said channelshave said one character depending upon whether said rst device is in oneor the other of its extreme positions or is in itsv intermediateposition, of means governed by said second device for controlling saidcommunication system so that the code elements transmitted over saidchannels both have said other character when said second device is inits operated position, means governed by said iirst device renderedeffective whenever said iirst device occupies its intermediate positionfor establishing the transmission of two sets of code elements when saidfirst device subsequently f moves into an extreme position, with thecharacter of the iirst set of code elements controlled by said firstdevice and that of said second set controlled by said second device, twoindication relays at said office one for each channel, a pickup circuitfor each indication relay supplied said one character is i lover saidbranch path with energy only when a code element of said one characteris transmitted over the associated channel and including a back contactlof the other indication relay, a stick circuit effective if anindication relay element of said one character transmitted over itsassociated channel to maintain that relay picked up until code elementsare lsubsequently' transmitted over said channels, means controlled bysaid two indication relays for indicating at said oilice the positionoccupied at said station by said first device, another relay at saidoice, a rst circuit for picking up said other relay completed when bothsaid indication relays are released, a second circuit for picking upsaid other relay completed when a code element of transmitted over oneof said channels and the indication relay associated with the other ofsaid channels is picked up, a third indication relay at said oice, abranch path in said second circuit including a front contact of saidother relay for picking up said third indication relay, stick circuitmeans effective if said third indication relay is picked up to hold thatrelay picked up until code elements subsequently are received at saidoffice, additional stick circuit means for said third indication relayeffective during receipt of code elements if said other relay is pickedup and a code element of said one character is received when theassociated indication relay is picked up, another stick circuit meansfor said third indication relay eiective when both indication relays arereleased, and means controlled by said third indication relay forindicating at said oflice the position occupied at said station by saidsecond device.

PAUL K. ECKHARDT.

No references cited.

is picked up by a code-

